1. Field of the Invention
This invention relates to computer systems, and more particularly, to power conservation in computer system processors.
2. Description of the Related Art
Modern computer system processors consume a significant amount of power. It is not uncommon for the current consumption of a modern processor to exceed 100 amperes. Thus, such a processor may easily consume in excess of 100 watts of power even at system voltages as low as one volt. High power consumption can generate large amounts of heat, which if left unchecked, can adversely affect the operation of the processor and the computer system in which it is implemented. Thus, high power consumption and the potential for excess heat generation place significant engineering demands on the design of computer systems.
Various methods of power conservation are employed in computer systems. In many computers, various system components that are inactive may be powered down for the duration of their inactivity. In many computer systems, processors are only powered down when the entire system is in an idle state. Some processors may allow for the powering down of individual processor units (e.g., a bus interface unit) if the unit is inactive. However, the core of a processor typically cannot be powered down during system activity. The current consumed by the core of a processor may account for a large amount of its overall current consumption. Furthermore, activity in the core typically affects other units within the processor, and often times the entire computer system, and thus serves as a major driver of overall power consumption.